Infertility in Sheep and Goats Flashcards
How can you measure the fertility of a flock?
% barren and % pregnant
How can you measure the fecundity of the flock?
Number of lambs/kids born per pregnancy
How can you measure the survival rate of a flock?
Number of lambs/kids that survive to weaning
How can you measure the lambing percentage?
Number of lambs reared/weaned/sold per 100 ewes put to the ram
What is the energy requirements for pregnant ewews?
Single 1.5 x maintenance
Twins 1.9 x maintenance
What should you compare a flocks reproductive performance with?
Previous records
MLC flockplan record for local area or breed
What are the factors responsible for poor lambing?
Poor conception rate
Poo ovulation rate
High embryonic/foetal death
Abortion/stillbirth/perinatal loss
Of the factors responsible for poor lambing percentage, which leads to…
- Increased single lambs
- Increased barren ewes
- Decreased ewes rearing a lamb
- Poor ovulation rate
- Poor conception rate and high embryonic death
- High abortion/stillbirth/perinatal loss
In general, what factors can cause poor conception rates?
Season Reproductive tract abnormalities Fertilisation failure Phyto-oestrogens Stress Mal infertility
How does season affect conception rate?
Breeding earl/late in breeding season results in poor conception rates because
= All animals may not be cyclic
= Possibilitys of short cycles in early breeding season
= Irregularity of cyclicity
What reproductive tract abnormalities can affect conception rate?
Freemartins
Intersex
Ovarian hypoplasia
Ovarian cysts
What are phyto-oestrogens? How do they affect conception rate?
Oestrogen like compounds produced by plants like red clover
Decreases conception due to changes in cervical mucous and sperm transport
How can you avoid stress affecting conception rate?
Avoid transport, shearing, foot-trimming, vaccination, worming and dipping around breeding time
What functional factors affect conception rate? How would you treat in sheep?
Pseudopregnancy/hydrometra/cloudburst
- Accumulation of aseptic fluid in uterues in presence of presistent CL
Reasons - lack on conception, early embryonic death, genetics
Treatment = PGF2-alpha and oxytocin
Factors affecting ovulation rate in sheep?
Season
Age
Genotype/breed
BCS
What is the ideal BCS at lambing for
Hill sheep
Lowland sheep
Hill - 3
Lowland - 3.5
How does a high or low BCS affect lambing percentage?
Decreased conception rate Decreased ovulation Increased embryonic loss Decrease lamb birth weight Decreased colostrum production
How can you manipulation ovulation rate in sheep? How does it work?
Season you bred in
Breed of sheep
BCS
Flushing
Increases follicle recruitment, selection and dominance
Factors affecting/causes of early embryonic death in sheep…
Asynchrony between embryonic development and timing of P4
Dietary intake = overfeeding inversly related to P4 conc
Age = uterine environment
Mineral deficiencies (Se, I)
Infections (Toxo, Border disease)
Factors affecting later foetal death in sheep..
Overfeeding in early pregnancy
Underfeeding in later pregnancy
When does most foetal growth occur in sheep? What can happen if you overfeed?
In last trimester
Overfeeding leads to plactenal insuffiency
Most common causes of late foetal death/abortion in sheep..
Chlamydophilia abortus
Toxoplasmosis
Campylobacter
Causes of pernatal mortality?
Stillbirth Diease - Watery mouth, viral diarrhoea/toxo/chlamydophilia Trauma Mineral deficiency (Cu, Co) Hypothermia - Poor mothering - Mis mothering
